No abstract

The synthesis and characterization of different series of methyl methacrylate/hydroxyethyl methacrylate (MMA/HEMA) copolymeric nanoparticles with different monomer feed compositions and utilization of them in entrapment and controlling the release of hydrophilic drug (sodium warfarin) and hydrophobic drugs (ibuprofen and praziquantel) were investigated. The polymeric nanoparticles and their entrapment with drugs were prepared using oil‐in‐water (O/W) differential microemulsion polymerization technique in the presence of polyvinyl pyrrolidone and polyethylene glycol as biocompatible emulsifiers as well as ammonium persulfate as an initiator. The effect of HEMA content in the monomer feed composition on the colloidal properties was studied, and it is found that the particle size Dv, turbidity, and the negative charge increase with increasing of HEMA content but the surface tension decrease. Moreover, the entrapment efficiency (EE) is affected by the content of HEMA in the monomer feed composition, the drug hydrophobicity, and the monomer to drug ratio. It is concluded that, EE into MMA/HEMA in monomer feed composition as 90/10, 70/30, and 50/50 is found to be (95.3–98)%, (84–96.9)%, and (69.5–94.6)% for sodium warfarin (with high hydrophilicity) as well as, ibuprofen and praziquantel (with high hydrophobicity), respectively. The entrapment of drugs in polymeric nanoparticles is confirmed by IR‐spectroscopy and transmission electronic microscopy. In vitro drug release experiments show that controlled release of drugs from copolymeric nanoparticles depend on HEMA content, the monomer to drug ratio, and the physiological pH. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

Nanosized particles derived from poly(methyl methacrylate) as well as copolymer of methyl methacrylate (MMA) and 2hydroxyethyl methacrylate (HEMA) were synthesized by differential microemulsion technique in the presence of ammonium persulfate as water-soluble initiator. The polymerization was stabilized by adding biologically safe emulsifiers namely the sodium dodecyl sulfate (SDS) or polyvinyl pyrrolidone (PVP) either alone or in conjunction with polyethylene glycol. The turbidity measurements, surface tension, f potential, and morphological characterizations of the obtained nanosized poly MMA and its copolymer with HEMA in different monomer feed compositions were investigated. It is found that increasing HEMA content leads to increase in the particle size, turbidity measurements but the negatively charged f potential decreased. However, when SDS is used, the surface tension of the prepared lattices increased, whereas it is decreased by using PVP. Kinetic studies of (MMA/HEMA) in ratio of 95/5 wt % in the presence of SDS or PVP revealed that the emulsifier concentration has a considerable effect on the rate of polymerization and the power of the emulsifier. The entrapment of drug was investigated using two active molecules different in water solubility (sodium warfarin and ibuprofen). It is noted that entrapment efficiency is independent of HEMA content in the monomer feed composition but dependent on type of drug and the amount of drug introduced. Hence, higher entrapment efficiency was attained for sodium warfarin (more hydrophilic) than that of ibuprofen (more hydrophobic) and they were 95.5 and 85%, respectively.

Three different composition ratios of polyvinyl acetate-g-polyoxyethylene monomethylether (MPOE-g-PVAc) were prepared in the presence of benzoyl peroxide as an initiator using a macroradical initiator technique. The grafted copolymers were characterized through Fourier transform infrared (FT-IR), nuclear magnetic resonance (NMR), and ultraviolet (UV) spectronomy; the rheological properties expressed as viscometry and creep analysis were also studied. The solutions of MPOE-g-PVAc are Newtonian in nature and by increasing the monomer content in the composition, the viscosity of the solution decreases. The creep analysis demonstrates that the resultant strain increases by increasing the monomer composition ratio.The effect of grafted copolymers on the physicomechanical properties of ordinary portland cement (OPC) pastes was investigated. The results showed that the addition of water mixed to the cement with graft copolymer improves most of the specific characteristics of OPC. As the concentration of the grafted copolymer increases, the water-to-cement (WC) ratio as well as setting time decreases. The combined water content increases with the addition of copolymer to the mixing water. The compressive strength was sharply increased at nearly all hydration ages.

No abstract